Manual tapping a ferrule question

ekb6760

ekb6760

Misplaced Texan
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When tapping a ferrule made from rod stock, I generally tighten the 1/4" drilled piece of material stock into the 3-jaw chuck and use my 5/16" x 18 tap to cut the threads. The problem is that the material always starts to slip and turn in the chuck before I get the threads completely cut. QUESTION: Is there a "special trick" to keep the material from slipping? I am not set up for live threading, so I cut the tenon threads with a die, and I've had good results cutting clean usable threads by applying wax to the tenon. But the problem of the ferrule material slipping gets irritating, and should I attempt to cut ferrule threads in Ivory, could get expensive, due to the brittleness of that material.

Any good advice would be appreciated.
 
Are you trying to run it straight through?
I run it in a bit, back it out, run in some more, back it out
Probably 4 times backing it out and continue ing till the end
 
What kind of tap ?
Start with a spiral tap . Finish with a bottoming tap.
Wrapping the ferrule on sanding paper might not be a bad idea for better grip.
Indicate to make sure you're running true .
 
cuejo said:
Are you trying to run it straight through?
I run it in a bit, back it out, run in some more, back it out
Probably 4 times backing it out and continue ing till the end
Click to expand...

I'm making capped ferrules with a glue relief hole. I don't try to run it through all at once, if that's what your asking. I pretty much do it like you describe, but before I finish cutting the threads, the tap just gets to tight in the material and causes it to slip and turn in the chuck.

I was thinking using a drop or two of oil on the tap for the last bit of cutting might help. Do you think that would be a good course of action?
 
JoeyInCali said:
What kind of tap ?
Start with a spiral tap . Finish with a bottoming tap.
Wrapping the ferrule on sanding paper might not be a bad idea for better grip.
Indicate to make sure you're running true .
Click to expand...

I like that idea Joey. I'll order the bottoming tap tomorrow. I'll try the sand paper trick on my next ferrule.
 
ekb6760 said:
.
I was thinking using a drop or two of oil on the tap for the last bit of cutting might help. Do you think that would be a good course of action?
Click to expand...
Oil...no, some wax on the tap ..yes. Also, I back the tap all the way out at least 2-3 times, and at the same time, I use a basketball filler needle on my air hose to blow the debris out of the ferrule. I have a small piece of small dia. hose attached to it and I place it at the bottom of the hole so it blows everything back out so the tap doesn't bind up on the debris at the bottom of the hole.
Some ferrule materials tend to be more troublesome then others. A key item...Tighten the chuck as tight as you can... you will not crush or distort the ferrule so have at it.
Hope this helps.
dave
 
ekb6760 said:
When tapping a ferrule made from rod stock, I generally tighten the 1/4" drilled piece of material stock into the 3-jaw chuck and use my 5/16" x 18 tap to cut the threads. The problem is that the material always starts to slip and turn in the chuck before I get the threads completely cut. QUESTION: Is there a "special trick" to keep the material from slipping? I am not set up for live threading, so I cut the tenon threads with a die, and I've had good results cutting clean usable threads by applying wax to the tenon. But the problem of the ferrule material slipping gets irritating, and should I attempt to cut ferrule threads in Ivory, could get expensive, due to the brittleness of that material.

Any good advice would be appreciated.
Click to expand...
If you are tapping 5/16x18, drill a "17/64" final hole instead of a 1/4". I think that is your biggest problem. You may want to drill a pilot hole first before drilling to final size. Don't try to tap all at once, go in and out a few times and be sure you have a new sharp tap. You don't need any lub, if your tap (very important) is sharp and you are careful it will tap pretty easy.

Another trick is to drill a 1/4 hole first and follow that with a 17/64 bit that you have modified. Take the 17/64 and grind the tip flat like an end mill so you get a nice perfectly flat bottomed hole for your tenon. It is also important to work carefully there is no hurry.

If you are using strip type ferrule rod material, it is possible to split the ferrule when drilling and tapping. You may not even see it when you are making the ferrule till it splits sometime later. You don't want any stress on the material as you are describing with the stuck tap, making the ferrule should all go quite easily.

You mention your die. You can make really nice tenon threads with dies you make yourself. You need at least two. Just take a piece of aluminum rod and drill and tap it to make your own die. After you have done this you need to cut a small way into the end of the rod/die with a hack saw to create the cutting edges of the tap. The trick is to make more then one with different size holes.

When making the threads just start with the larger hole die and progress to the smaller ones. You will get a nice smooth thread. When you are done you can finish it by threading on a steel nut for a final fit check. When doing it this way you don't have to turn the tenon down so much.

You can turn it to around .302. Practice this on scrap to see what you want to use as your size, there is no real rule but you would like it to be as big as possible.
 
Last edited:
I’ve noticed a BIG difference depending on the tap. I went from a 4 flute set to a 3 flute. Much better. Now I'm using a 2 flute set. No slipping at all. I strongly recommend ordering a 2 flute set.
 
You can drill for a 5/16-18 thread , as big as 7mm, It does seem big , but the thread strength will not be compromised by very much at all.
The cutting load will be significantly reduced with the bigger minor diameter.
A lot of tapped holes are now going to much larger minor diameter taped holes in the engineering sector. The benefits are stronger drills, faster tapping with less chip load and less chip volume, while still being strong enough to handle the high tensile fasteners.
With some materials that are brittle or delicate, I make a split sleeve usually from ali to hold the parts. It acts like a poormans collet and also gives more support to the part being processed. So the chance of the part splitting or spinning in the chuck is greatly reduced. With a recessed sleeve, it can be used as a length stop and to hold very short pieces as well.There are lots of uses for simple split sleeves.
Neil
 
Dave38 said:
Oil...no, some wax on the tap ..yes. Also, I back the tap all the way out at least 2-3 times, and at the same time, I use a basketball filler needle on my air hose to blow the debris out of the ferrule. I have a small piece of small dia. hose attached to it and I place it at the bottom of the hole so it blows everything back out so the tap doesn't bind up on the debris at the bottom of the hole.
Some ferrule materials tend to be more troublesome then others. A key item...Tighten the chuck as tight as you can... you will not crush or distort the ferrule so have at it.
Hope this helps.
dave
Click to expand...
I especially like the idea of using the air hose needle. Very inventive. Thanks for the help Dave.
 
macguy said:
If you are tapping 5/16x18, drill a "17/64" final hole instead of a 1/4". I think that is your biggest problem. You may want to drill a pilot hole first before drilling to final size. Don't try to tap all at once, go in and out a few times and be sure you have a new sharp tap. You don't need any lub, if your tap (very important) is sharp and you are careful it will tap pretty easy.

Another trick is to drill a 1/4 hole first and follow that with a 17/64 bit that you have modified. Take the 17/64 and grind the tip flat like an end mill so you get a nice perfectly flat bottomed hole for your tenon. It is also important to work carefully there is no hurry.

If you are using strip type ferrule rod material, it is possible to split the ferrule when drilling and tapping. You may not even see it when you are making the ferrule till it splits sometime later. You don't want any stress on the material as you are describing with the stuck tap, making the ferrule should all go quite easily.

You mention your die. You can make really nice tenon threads with dies you make yourself. You need at least two. Just take a piece of aluminum rod and drill and tap it to make your own die. After you have done this you need to cut a small way into the end of the rod/die with a hack saw to create the cutting edges of the tap. The trick is to make more then one with different size holes.

When making the threads just start with the larger hole die and progress to the smaller ones. You will get a nice smooth thread. When you are done you can finish it by threading on a steel nut for a final fit check. When doing it this way you don't have to turn the tenon down so much.

You can turn it to around .302. Practice this on scrap to see what you want to use as your size, there is no real rule but you would like it to be as big as possible.
Click to expand...

I know I have a 17/64 bit around here somewhere, just never used it before. Thank you for your ideas & help.
 
DanO said:
I’ve noticed a BIG difference depending on the tap. I went from a 4 flute set to a 3 flute. Much better. Now I'm using a 2 flute set. No slipping at all. I strongly recommend ordering a 2 flute set.
Click to expand...
Will do on Monday. Thank you for your help.
 
conetip said:
You can drill for a 5/16-18 thread , as big as 7mm, It does seem big , but the thread strength will not be compromised by very much at all.
The cutting load will be significantly reduced with the bigger minor diameter.
A lot of tapped holes are now going to much larger minor diameter taped holes in the engineering sector. The benefits are stronger drills, faster tapping with less chip load and less chip volume, while still being strong enough to handle the high tensile fasteners.
With some materials that are brittle or delicate, I make a split sleeve usually from ali to hold the parts. It acts like a poormans collet and also gives more support to the part being processed. So the chance of the part splitting or spinning in the chuck is greatly reduced. With a recessed sleeve, it can be used as a length stop and to hold very short pieces as well.There are lots of uses for simple split sleeves.
Neil
Click to expand...
I use those as well. Very useful. Thanks for your help. Also, I love reading your posts, I find them very informative. Love your cues as well.
 
Sorry for the intrusion since I'm not a cue builder or a machinist. Only a tool nerd.
First depending on what chuck you have and or if you're a purist or not YOU SHOULD ALWAYS key every Jaw. Your have 3 or 4 opportunities to tighten the jaws. Use them. I used to work for Jacobs.

Selecting Taps. Tap selection is all about chip management. Research your material and its chip. I'm going to assume ferrule material is a long stringy chip. But even if not, with a blind hole you need to bring the chip back out the hole. Joey's suggestion of a Spiral Flute tap will help with this.

Conetip's suggestion of having less % of thread engagement I think is a safe bet since after all, you're gluing the parts too. The threads IMO just gives more surface area for the glue. I can't argue this comment, its just what I'm thinking.

When I was in the tap business, my manager told me something to help me solve problems that stuck with me. "Think like a tap." "How can I manage this chip? "
 
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